Einfluss keramischer Partikel- und Faserverstärkungen in Metall-Matrix-Verbundwerkstoffen auf das VHCF-Verhalten

在技术操作过程中，高性能材料经常暴露于循环载荷条件下，导致损伤累积直至最终致命断裂。同时，对于部件的主要部分，要求在没有任何损坏的情况下进行高次数的循环。拟议项目的目的是研究Al-Al 2 O3金属基复合材料在超高周疲劳（VHCF）范围内的循环变形行为，这取决于增强材料（颗粒、纤维）的几何形状以及基体材料（T6和过时效）的强度。因此，除了经典的显微结构分析方法外，还将建立红外热成像以及谐振频率和损伤参数的分析，以确定损伤的开始以及局部损伤区域。因此，可以获得关于损伤累积的信息。从实验观察开始，Weibull分布的Al-Al_2 O_3金属基复合材料的损伤行为将使用随机模型，这提供了可能性的损伤概率的确定。此外，陶瓷增强体对超高周疲劳寿命的影响将通过新开发的模型进行研究和描述。因此，拟议的项目一方面给出了寿命的实验变化的描述，以及澄清这种类型的材料在非常高的循环疲劳制度的可能应用的重大贡献。

During technical operation, high performance materials are very often exposed to cyclic loading conditions leading to damage accumulation until the final fatal fracture. At the same time, quite high requirements with regard to high number of cycles without any damage are claimed for major part of components. The aim of the proposed project is the investigation of the cyclic deformation behaviour of Al-Al2O3 MMCs in the range of very high cycle fatigue (VHCF) in dependence both on the geometry of the reinforcement (particles, fibres) as well as on the strength of the matrix material (T6 and overaged). Hence, besides the classical methods of microstructural analysis the infrared thermography as well as the analysis of the resonant frequency and the damage parameter will be established in order to determine the beginning of damage as well as the local damage area. Therefore, information on the damage accumulation can be obtained. Starting from experimental observations, the Weibull distributed damage behaviour of Al-Al2O3 MMCs will be described using stochastic models, which offers possibilities for the determination of damage probabilities. Moreover, the influence of the ceramic reinforcements on the very high cycle fatigue life will be investigated and described by newly developed models. Thus, the proposed project gives on one hand a description of the experimental variations of the life times as well as a significant contribution to the clarifying of a possible application of this type of material in the very high cycle fatigue regime.